Emergency workers respond to a massive pileup accident on Interstate 25 in Denver on Saturday, March 1. (Kathryn Scott Osler, The Denver Post)

Somewhere between the overpasses for Downing and Logan streets, as Doug Newkirk headed north on Interstate 25 in Denver, the weather swallowed his car — as it would 103 other vehicles along a roughly mile-and-a-half stretch. Newkirk found himself cast into a nightmare of spinning red taillights and utter helplessness, one part of a chain-reaction traffic accident unlike any that police investigators have seen. Vehicles careened in all directions, the lives and stories of strangers intersected in improbable ways, and narratives of astounding good fortune were juxtaposed with emotional devastation.

"I've never been in a snowstorm that happened that quick or that bad, instantly," says Newkirk, 72. "Seemed like you drove through a wall of snow. All at once, the car wouldn't steer, the car wouldn't stop, the car wouldn't do nothin' is about what it amounted to. We were going at that truck and there was nothing I could do about it."

The truck — a tractor-trailer — jackknifed ahead of him and slid into a barrier along the far right lane.

Becky, Newkirk's wife of 32 years, sat in the front passenger seat. They had driven out from Stillwater, Okla., in the 2013 Chevrolet Sonic purchased a little more than a year earlier in anticipation of long drives in their retirement. Already, they had racked up about 27,000 miles, as they headed to visit Becky's mother.

Where I-25 dips into a shadowy, high-walled channel — speed limit 60 mph — a sudden, isolated blast of snowshowers coated the pavement in white and produced a dense curtain of swirling flakes.

Just before they lost control, Becky said: "Where did all this come from?"

Those are the last words Newkirk remembers. Later, someone would tell him that his car had been bumped from behind, but all he recalls is that on the suddenly slick stretch of road, he felt that whatever would happen in the next few seconds was entirely out of his hands.

From left, Michael Aguayo, Capt. Justin Harper and Dustin Morgan of Denver Paramedics stand on the Washington Street bridge, which overlooks the I-25 stretch where the March 1 pileup took place. Aguayo and Morgan had been on Buchtel Boulevard that morning, driving parallel to that sunken stretch of I-25., when Aguayo looked down and saw the wreckage. (Hyoung Chang, The Denver Post)

"There was nothing I could do," he says. "Luckily, the Lord let me ..."

His voice trails off as he tries to explain the welcome state of shock, the lost memory, that coincided with the Chevy's impact against the left rear corner of the trailer. The impact that left him bleeding and disoriented but killed his 61-year-old wife.

"I don't know where I went," Newkirk says, "but before I hit that truck, something happened. And I woke up in the ambulance."

Multiple fatalities?

Although it all stemmed from the same March 1 confluence of icy, fast-moving weather and a flash-frozen stretch of pavement, you could slice and dice the ping-ponging vehicles into perhaps as many as 200 individual accidents along the interstate from Logan Street to University Boulevard, police say.

In a final accounting at once miraculous and heartbreaking, the chain reaction of collisions claimed only a single death — Becky Newkirk, who died at the scene.

Ultimately, authorities decided not to file criminal charges in an accident triggered by such rapidly changing weather conditions, with no clear way to pinpoint what set the chain of events in motion.

Paramedics Dustin Morgan and Michael Aguayo had been on Buchtel Boulevard that morning, driving parallel to and overlooking that sunken stretch of I-25. As Morgan periodically tapped the brakes, testing their ambulance's deteriorating traction, Aguayo looked down and saw the wreckage extending south into the distance.

David Rasmussen of Colorado Springs, accompanied by his dog Ohana, returns to the site of the massive March 1 pileup in which he and his black Lab were involved. "Once I realized my hound was OK," Rasmussen recalls, "I purposely went up to people so they could pet her. It made her feel good. It made people feel good." (Hyoung Chang, The Denver Post)

"I was expecting to have multiple fatalities, based on the amount of damage and sheer carnage and the whole situation," Morgan recalls. "I went from car to car, banging on the hood, giving thumbs-up to people, asking if anybody was injured. I saw mostly people rendering aid to each other. I think it was more of a kinship, a show of humanity."

Road turns white

David Rasmussen felt a sudden sense of urgency as he cruised north on I-25, headed to visit his girlfriend in Greeley, and — at 60 mph — saw the road before him turn white.

He was already off the gas of his Toyota Tacoma pickup when he first saw a car spin out well ahead of him. He hit the brakes. Nothing. He shifted into four-wheel drive, saw an opening to his right and began moving toward the emergency lane.

He steered hard into the concrete barrier, whose flared base caught his tire and slowed him down a bit as other vehicles continued to zoom past. An 18-wheeler loomed just ahead.

He watched a reddish car slam into the back left corner of the rig. Rasmussen guesses he was only moving about 10 mph when he rammed flush into the rear of the trailer, but his air bags deployed.

That sudden burst proved particularly traumatic for his dog, a 45-pound black Lab named Ohana, seated in the front passenger seat. Although Rasmussen reached across to brace her, the air bag's force pushed Ohana, yelping in distress, to the floorboard.

When Rasmussen, a 60-year-old carpenter from Colorado Springs, finally gathered himself, he realized the dog was OK — just stunned. He turned his attention to the car and its occupants next to him.

A former emergency medical technician, Rasmussen gauged the damage to the vehicle and drew a quick, somber conclusion that was confirmed when he could not find a pulse. Other travelers gathered around the badly injured woman and her dazed husband.

From the back of his truck, Rasmussen took a blanket to cover them both as snow filtered through the space where the windshield used to be. He saw an ambulance arriving and waved it over.

As everyone waited for the accident to clear, he figured there was at least one thing he could do to help.

"Once I realized my hound was OK," Rasmussen says, "I purposely went up to people so they could pet her. It made her feel good. It made people feel good."

Narrow openings

In the moments before what seemed an inevitable impact, Bruce Haskins told his wife to hang on. He applied steady pressure to his brakes, slipped through a couple of narrow openings between vehicles and somehow glided their Toyota Highlander to a stop about 10 feet from two cars that had collided in front of him.

Untouched.

The semiretired, Bismarck, N.D., couple had spent February in Phoenix and were headed home, with a stop in Fort Collins to visit an adult daughter.

They stopped just ahead of the reddish Chevy Sonic, within a few feet of where bystanders rushed to the vehicle and realized a woman had died.

Then Haskins and his wife, Margo, approached Doug Newkirk, who was disoriented, bleeding from a small gash in his head. He kept asking, "Is she OK?"

Margo knew Newkirk's wife was gone but didn't feel it was her place to tell him. Instead, she simply said, "I think they're trying to keep her warm."

She sat with Newkirk beneath the raised hatchback of a nearby vehicle, holding a rag to his head until the bleeding stopped while others wrapped him with beach towels and blankets.

He said he wanted to see his wife.

"So I walked with him over to his car," Margo recalls. "He said, 'I just need to see her.' But she was covered up with a blanket. I know at that time he knew — he said, 'She's gone.' I said, 'Doug, I don't know that for sure.'

"When we put him into the ambulance, he didn't want to go. I didn't blame him. I wouldn't want to leave my loved one, even if they were gone."

Hours later, Bruce Haskins cleared the debris away from his car and got permission to leave the scene. Before resuming their journey, the couple stood in the middle of I-25 and embraced.

"Then we looked back at what we'd just been in," Bruce says, "and thanked our lucky stars."

Devastated

The driver of the semi, 51-year-old Gina Bocanegra, says she already had come to a stop when she felt the impact of something hitting the back of her rig.

She didn't realize until a firefighter told her: A woman had died when the car in which she was riding struck the back of the trailer.

Bocanegra says she felt devastated.

Again.

One night in 2010, she was driving her crippled rig southbound on I-25, near Las Vegas, N.M., moving at slow speed in hope of making it to Albuquerque, where she could get repairs.

She apparently didn't realize until an officer contacted her that a thump she felt minutes earlier had actually been a fatal accident: According to the police report, an 18-year-old man had crashed into her from behind and died at the scene.

She says she was never ticketed or charged, although the victim's family sued her insurance company for wrongful death and settled.

"It's a part of the job we go through. There's nothing we can do, especially when they slam into you, there's nothing you can do about it," says Bocanegra, a Phoenix-based driver who has been on the road for the past 12 years. Still, the news that a second person had died in a collision with her trailer landed hard.

"At first, I was in shock, it took a while to register," she says. "All I can do is offer prayers for the husband for his wife. What else could I do?"

Bocanegra says she can't discuss the accident itself. But she notes that she has been able to get back behind the wheel with the support of family and with the help of other drivers who have had similar experiences — including multiple fatal accidents.

"I have some really good friends, they've been through something like this already," she says. "Like they said, it comes with the job, you have to accept it and there's nothing you can do about it. If you hold it in, you start drinking or doing other things you shouldn't be doing. ... All I can do is offer prayers. I just thank God more people didn't get hurt."

A quick decision

At first glance, Carlos Davila's blue 2007 Subaru Impreza looked to first responders like the site of a certain second fatality. Then they looked inside the vehicle, whose windshield had been crushed when it submarined the back end of another car, and saw no one.

Davila, 23, seen above with Mariah Davila, had been on his way home to Lakewood after a shift working at a car-care center. He didn't normally take I-25, but as he approached the highway heading west from Evans Avenue, he saw traffic moving well and made a quick decision to reroute.

When he ran into the bad weather and saw the constellation of flashing taillights, he downshifted and hit the brakes, which locked and left him skidding out of control. He turned into the center median to slow his progress but soon found himself in the middle of what he called a "Subaru sandwich."

He rammed the Subaru ahead of him while another Subaru struck him from behind. Next thing he knew, the rear of the car ahead of him was practically in his front seat.

"I was pretty dizzy, couldn't see anything really," Davila says. "After the two impacts, I got scared. I thought it would keep getting hit, the windshield would keep caving in."

Still foggy from the impact, he managed to crawl out through the right passenger door. He wandered toward the spot where a reddish car had struck the back of a semi and, as people attended to a woman, slowly realized that something awful had happened.

"Horrible" was the word he used to describe the scene to his wife, Mariah, 22, when he reached her on the phone.

Before it even dawned on him that he easily could have been killed, he thought about how upset Mariah would be that he had totaled the Impreza.

It wasn't that Mariah loved the car. In fact, she hated it. She had told him not to buy it. But it was his "affordable dream car," a ride he tinkered with and upgraded and pampered and even named Mr. Rumbles, because he so loved the way the engine sounded.

That said, Mariah now looks at the photos of the crash, of her husband's ride crushed between two other vehicles, and feels a pang of gratitude.

"I'm glad the car took the impact and Carlos didn't," she says.

When they replace it, she allows that they'll probably get another model like it, but without all the fancy extras. Carlos, a living epitaph for Mr. Rumbles, can deal with that.

"How often do you get to say my dream car was not only beautiful and fast but saved my life?" he says.

Defensive driving

As brake lights and spinning objects suddenly surrounded him, Mike Murray instinctively recalled a lesson in defensive driving from his Montana home, where wildlife have been known to wander into traffic: Don't swerve for deer.

Fast-moving vehicles, he quickly decided, were another matter entirely.

Murray, a 29-year-old singer-songwriter and guitarist in a blues-rock band, braked to avoid one logjam ahead, but immediately realized the road was too slick to stop in time. He swerved left and dodged one knot of vehicles.

Beside him, Chris Krager, the bass player, tried in vain to track everything moving around them. He opened his eyes wider and wider but still couldn't process what was happening.

"I just remember thinking that I'm disappointed in myself," Krager recalls. "I thought, what a stupid way to go out — a car wreck. This little stretch of road? Is this where my wife will come to visit? Is this where I come to my end?"

Murray swerved right, found an open lane and avoided another collision before the odds caught up with him and the right rear of his car slammed into something — the first accident of his driving life. His Subaru Outback came to rest just a few yards behind the Newkirks' demolished Chevy Sonic.

Murray and Krager, like nearly everyone else at the scene, milled about searching for anyone who needed assistance. They realized the tragic outcome in the Chevy as others converged on that vehicle. Turning to others in need, Murray gave his jean jacket to a young woman, shivering in workout clothes, who had been on the way to the gym.

Hours later, once he and Krager procured a rental car, packed it with their only mildly damaged musical equipment and continued home to Montana, they had two days' worth of highway miles to consider what had just happened to them.

"Everything has a brand new freshness to me," says Krager, 44. "We stopped for a burrito, and I thought it was the best burrito I'd ever had in my life."

They spoke about how everyone at the accident site had come together, acted kindly and selflessly in a way they agreed was inspiring. Yet over all of that hung the shadow of a lost life.

Murray recalls walking up a highway-entrance ramp, as many did that day, to use the rest room at a nearby Whole Foods store. Stepping from the disaster zone into the grocery store, he was struck — even slightly angered — by this proximity of tragedy and normalcy.

"I quickly realized that's not wrong," Murray says. "Tragedy happens all the time, all around the world, and we go about our day. Then it touches us and changes us forever. Things like that stick around. That may be something I turn into a song."

Out of control

Doug Newkirk's next memory after the moment before impact is gradually regaining his senses in an ambulance with no clue what he was doing there.

Then he heard someone ask if anyone else had been in the car, and another voice say something about a DOA, and he began to understand: Becky was gone.

He has replayed in his mind the moments before the collision, those seconds when the world spun out of control.

"Only thing I've thought about was if I could've made that car go a little bit to the right, all these big trucks have a bumper down low to catch them cars," he says. "It's just a matter of inches, and the car wouldn't steer."

He bears no ill will about the accident. People have told him his car was bumped from behind, but he insists that if that's the case, that driver had no more control than he did. As for the driver of the semi, he says that she has his deepest sympathies. He used to drive a big rig in the 1970s.

"I was told they decided it was a no-fault situation, and that's what it had to be," Newkirk says. "I don't care how good a driver they are — till they've drove a truck on something like that, they've never drove. That woman's got to have nightmares."

Newkirk does. Twice, so far.

"Matter of fact, I just sat up about 4 o'clock this morning in a sweat," he says. "I run that truck again. Scared the hell out of me. My dogs even took off. I don't know what I said."

But now he says this: He will never again find himself traveling through Denver on Interstate 25. It is the place where he lost control, and the place he lost Becky.

"It'll never happen," he insists. "I'll drive 5,000 miles to go around I-25."